Linux | Linux学习笔记总结 : OpenVpn , Salt多master集群 , Vsftpd服务 , DNS域名系统 | Natural Language Processing library
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Linux学习笔记总结: OpenVpn,Salt多master集群,Vsftpd服务,DNS域名系统,yum,zimbra..........
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- Main entry point .
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- urls the job
- load config file
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Lines of Code : 2License : Non-SPDX (Apache License 2.0)
Copydef _is_linux():
return platform.system() == "Linux" def is_linux():
return platform.system() == 'Linux' Community Discussions
Trending Discussions on Linux
QUESTION
I am practicing regular expressions in Kotlin and trying to start with a multiline string. However, I am not receiving any matches. I feel like I am doing it right and can't figure out the problem.
Test lines:
...ANSWER
Answered 2021-Jun-15 at 21:32Here is how it works:
QUESTION
In C++20, we got the capability to sleep on atomic variables, waiting for their value to change.
We do so by using the std::atomic::wait method.
Unfortunately, while wait has been standardized, wait_for and wait_until are not. Meaning that we cannot sleep on an atomic variable with a timeout.
Sleeping on an atomic variable is anyway implemented behind the scenes with WaitOnAddress on Windows and the futex system call on Linux.
Working around the above problem (no way to sleep on an atomic variable with a timeout), I could pass the memory address of an std::atomic to WaitOnAddress on Windows and it will (kinda) work with no UB, as the function gets void* as a parameter, and it's valid to cast std::atomic to void*
On Linux, it is unclear whether it's ok to mix std::atomic with futex. futex gets either a uint32_t* or a int32_t* (depending which manual you read), and casting std::atomic to u/int* is UB. On the other hand, the manual says
The uaddr argument points to the futex word. On all platforms, futexes are four-byte integers that must be aligned on a four- byte boundary. The operation to perform on the futex is specified in the futex_op argument; val is a value whose meaning and purpose depends on futex_op.
Hinting that alignas(4) std::atomic should work, and it doesn't matter which integer type is it is as long as the type has the size of 4 bytes and the alignment of 4.
Also, I have seen many places where this trick of combining atomics and futexes is implemented, including boost and TBB.
So what is the best way to sleep on an atomic variable with a timeout in a non UB way? Do we have to implement our own atomic class with OS primitives to achieve it correctly?
(Solutions like mixing atomics and condition variables exist, but sub-optimal)
...ANSWER
Answered 2021-Jun-15 at 20:48You shouldn't necessarily have to implement a full custom atomic API, it should actually be safe to simply pull out a pointer to the underlying data from the atomic and pass it to the system.
Since std::atomic does not offer some equivalent of native_handle like other synchronization primitives offer, you're going to be stuck doing some implementation-specific hacks to try to get it to interface with the native API.
For the most part, it's reasonably safe to assume that first member of these types in implementations will be the same as the T type -- at least for integral values [1]. This is an assurance that will make it possible to extract out this value.
... and casting
std::atomictou/int*is UB
This isn't actually the case.
std::atomic is guaranteed by the standard to be Standard-Layout Type. One helpful but often esoteric properties of standard layout types is that it is safe to reinterpret_cast a T to a value or reference of the first sub-object (e.g. the first member of the std::atomic).
As long as we can guarantee that the std::atomic contains only the u/int as a member (or at least, as its first member), then it's completely safe to extract out the type in this manner:
QUESTION
Meson/Ninja provide an easy method to run a script at install time.
For example, this line will tell Meson to run the glib-compile-schemas command to compile the GSettings on Linux (system configuration options).
meson.add_install_script('glib-compile-schemas', schemas_dir)
(this command will be automatically run when the user executes ninja install)
How can I tell Meson to run a custom command at uninstall?
In this specific case I would like to delete (or at least reset to default) the key-value pairs in GSettings. To reset them, I have found that the command is gsettings reset-recursively (successfully tested in terminal).
ANSWER
Answered 2021-Jun-15 at 18:46Adding custom uninstall script is still being discussed, it's proposed quite some time ago but not yet implemented. It looks this task is typically left for package manager (and therefore to corresponding packaged scripts).
But I agree, there is some illogical asymmetry in case of meson install command. As a workaround, you can create your own target:
QUESTION
I have Windows 10 Pro Version 21H1 Build 19043.1052.
I have followed the guide in https://docs.microsoft.com/en-gb/windows/wsl/install-win10#step-4---download-the-linux-kernel-update-package and in Win 10 WSL won't set default 2 to get wsl. And I want to upgrade to version 2. I installed the regular Ubuntu from the Microsoft app store. And I did wsl --setdefault Ubuntu followed by wsl --set-default-version 2 and it only gave me For information on key differences with WSL 2 please visit https://aka.ms/wsl2. But wsl -l -v was still showing VERSION 1.
So I went an installed Ubuntu-20.04 LTS and now that version is showing VERSION 2 but not the regular Ubuntu one.
How can I get them both to version 2?
...ANSWER
Answered 2021-Jun-15 at 15:47When you do --set-default-version, you're setting the version for future distributions that you install. That doesn't convert or change any current distros you have installed. So for your existing Ubuntu distro that is version 1, you should use the wsl --set-version command to convert it to version 2 or revert back to version 1.
Source: https://docs.microsoft.com/en-us/windows/wsl/install-win10
QUESTION
I am practicing regular expressions in Kotlin and trying to start with a simple string. However, I am not receiving any matches. I feel like I am doing it right and can't figure out the problem.
Test String:
VERSION_ID="12.2"
And what would I do this for multiple lines:
...ANSWER
Answered 2021-Jun-15 at 04:10The version ID value inside your string appears to be surrounded with double quotes. Also, I suggest making the decimal portion optional, in case some versions might not have a minor version component:
QUESTION
I am getting a bad request response to my request. I have checked with an online JSON validator my dictionary data to be correct, and everything seems fine.
My code is the following:
...ANSWER
Answered 2021-Jun-15 at 11:58You are telling your server, you are sending JSON data, but the request body is not a JSON string but a url-encoded string (because that's the default behaviour of $.ajax() when you pass an object as data).
Use JSON.stringify, to pass a correct JSON body
QUESTION
I just reinstalled Fabric Samples v2.2.0 from Hyperledger Fabric repository according to the documentation.
But when I try to run asset-transfer-basic application located in fabric-samples/asset-transfer-basic/application-javascript directory by running node app.js the wallet is created and an admin and user is registered. But then it tries to invoke the function as given in app.js and shows this error
ANSWER
Answered 2021-Jan-29 at 04:04In my opinion, the CORE_VM_DOCKER_HOSTCONFIG_NETWORKMODE setting seems to be wrong.
you can check docker-compose.yaml or core.yaml
- I will explain fabric-samples/test-network as targeting according to your current situation.
- You can check in
CORE_VM_DOCKER_HOSTCONFIG_NETWORKMODEin docker-compose.yaml - Perhaps in your case(fabric-samples/test-network), the value of
${COMPOSE_PROJECT_NAME}was not set properly, so it was set to_test. - Make sure the value is set correctly and change it to your network name.
QUESTION
I have an AWS ubuntu instance with the following network interfaces:
ens5, ip: 172.XX.XX.XX
A5TAP, ip:192.168.233.1 (VPN)
How do I udp port forward port 10000-10200 to 192.168.233.52:10000-10200? I tried a the obvious commands below for a single port 10009, but it is not working:
...ANSWER
Answered 2021-Jun-15 at 11:24I believe what you want is the following:
QUESTION
I am trying to run a test case which basically copies a file from my machine to a mock server running in docker. The same test works fine on Mac and Ubuntu. But on Windows it's getting failed with the following error:-
...ANSWER
Answered 2021-Mar-31 at 11:29The remote path must be /, not \.
And the argument to createCopyCommand cannot be Path, as on Windows, that will translate the / to \.
QUESTION
I made a node JS application using Hapi on Windows 10. After testing it locally, the script start would run without any problem. here is the start script inside the package.json
ANSWER
Answered 2021-Jun-15 at 10:13You need to quote the *: nodemon -e "*" src/server.js.
Unlike Windows' cmd, Linux shells expand wildcards (as you can see in the command actually run, above the error). In Windows it's up to the program you are calling to expand wildcards. Since that is what you want in case of nodemon, it worked "by chance" on Windows without escaping the asterisk because it doesn't have any special meaning to cmd, but in Linux it will get expanded and that's not what you want.
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